Ignition distributor advance control mechanism for a reciprocating engine



May 28, 1968 D. M. BURNIA ETAL 3,385,275

IGNITION DISTRIBUTOR ADVANCE CONTROL MECHANISM FOR A RECIPROCATINGENGINE 2 Sheets-Sheet 1 Filed Oct. ll, 1967 A TTORNEVS D. M. BURNIA ETAL3,385,275

May 28, 1968 IGNITION DISTRIBUTOR ADVANCE CONTROL MECHANISM FOR ARECIPROCATING ENGINE Filed Oct. 11, 1967 2 Sheets-Sheet 2 W/d 1/4/14 M.1 /07 6 fl/SO/V a fM A TTORNEVS United States Patent O 3,385,275IGNITION DISTRIBUTOR ADVANCE CON- TROL MECHANISM F OR A REOIPROCNL INGENGENE Donald M. Burnia, Pontiac, and William M. Hutchison, Allen Park,Mich., assignors to Ford Motor Company, Dearborn, Mich, a corporation ofDelaware Filed Oct. 11, 1967, Ser. No. 674,476 Claims. (Cl. 123-117)This mechanism is used with a dual diaphragm distributor to advance theignition timing when the engine is decelerating and also advance thetiming when engine temperature exceeds a predetermined maximum while theengine is idling. A housing is divided into lower and upper chambers bya plate carrying a thermally responsive valve. A pressure responsivevalve extends through the plate. The bottom of the housing fits into anopening in the intake manifold so intake manifold vacuum is applied tothe lower chamber. Hoses connect the upper chamber to the carburetorthrottle bore and to the advance diaphragm of the distributor andanother hose connects the lower chamber to the retarding diaphragm ofthe distributor. During normal operation, vacuum in the throttle borepasses through the upper chamber to position the advancing diaphragm.When the engine is decelerating, high manifold vacuum opens the pressureresponsive valve to transmit manifold vacuum into the upper chamber,thereby advancing the ignition timing. When the engine is idling atnormal temperature, a

manifold vacuum in the lower chamber acts on the retarding diaphragm toretard ignition timing for emission control. If the engine temperatureexceeds a predetermined maximum, the thermally responsive valve opens toadmit manifold vacuum to the upper chamber and thereby advance theignition timing.

SUMMARY OF THE INVENTION erational phases. Additionally, engine idlingwith retarded timing increases engine operating temperature since theengine is running less efiiciently, so it is desirable to eliminate thespark retardation when extended idling raises engine temperature to thepoint where damage to engine components is probable.

In the past, a combination of at least two devices was used to achievethese features. Multiple devices were considered necessary because itwas believed essential to locate the device for advancing ignitiontiming at idle in the engine cooling system or on the engine head, whilethe device for advancing the spark during 'decleration had to besubjected to intake manifold vacuum. In addition to the high materialcosts resulting from the use of multiple devices, installationprocedures were lengthy and complicated and did not lend themselves tomass production techniques.

The distributor control mechanism provided by this invention iscontained in a single housing attached to the engine intake manifold andgreatly reduces material and assembly costs. In a reciprocating internalcombustion engine having a metering device with an induction passagecontaining a throttle blade for supplying air to an ice intake manifoldof the engine and having an ignition distributor for distributingignition sparks to the engine, the distributor control mechanismcomprises a housing divided into first and second chambers by apartition. The first chamber is connected to the interior of the intakemanifold, while the second is connected to the induct on passageanterior of the throttle blade and to the spark advancing means for thedistributor. A pressure responsive valve is located within the housingfor connecting the second chamber to the intake manifold interior wh nmanifold vacuum exceeds a predetermined maximum. In addition, athermally responsive valve is located within the housing for connectingthe first and second chambers when its temperature exceeds apredetermined maximum.

During acceleration, road load operation, and idling at normaltemperatures, vacuum from the induction passage anterior of the throttleblade passes through the second chamber to position the spark advancingmeans on the distributor. Both of the valves in the control mechanismremain closed during the above operational phases. When the engine isdecelerating, the high manifold vacuum opens the pressure responsivevalve, which admits the manifold vacuum to the second chamber andthereby advances the timing. When the engine is idling, the temperatureof the intake manifold becomes representative of the engine temperature.Thus, when the engine temperature rises, the temperature of a thermalelement controlling the thermally responsive valve rises correspondinglyand opens the thermally responsive valve when a predeterminedtemperature is reached.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is an exploded view of thecontrol mechanism showing the structural relationship of the housing,the partition and the pressure responsive and temperature responsivevalves. Portions of the components are broken away to show internalstructure. FIGURE 2 is a schematic diagram showing the control mechanismof this invention with its connections to the carburetor, a dualdiaphragm distributor and the engine intake manifold.

DETAILED DESCRIPTION Referring to FIGURE 1, the control mechanism ofthis invention is made up of a lower housing 10 and an upper housing 12with a flat plate 14 serving as the partition dividing the interior ofthe assembled housing into a lower chamber 16 and an upper chamber 18.Lower housing 10 has a projection 20 formed on the bottom surface of twotubes 22 and 23 connected to a side. A lip 24 and a shoulder 25 surroundthe upper edge of the lower housing.

The valve body for the pressure responsive valve is a cylindrical memberindicated by numeral 26. Valve body 26 has its exterior flared at thebottom as represented by numeral 28 to fit into the interior ofprojection 29. A shoulder 30 is formed near the top exterior of body 26and external screw threads 32 are formed on the portion of body 26 aboveshoulder 30.

A large bore 34 extends into the interior of body 26 from the flared endand tapers into a smaller bore 36 at an interior shoulder 38. Positionedloosely in bore 34 is a valve member 40. A compressive spring 42 urgesvalve member 40 onto the seat formed by shoulder 38. Spring 42 is heldin place by a jet 44 threaded into the lower end of bore 34. The wall ofbody 26 contains a hole 46 communicating with bore 34 above jet 44.

Plate 14 has a large hole 50 near the center thereof and a small hole 52near one edge. A member 54 having a collar 56 formed around its upperend fits loosely in hole 52. A rubber O-ring 58 surrounds member 52 and3 seats against the lower surface of collar 56. Below plate 14, member54 is fastened to a bimetal strip 60 that is anch red to plate 14.Member 54, strip 60, and associated parts make up the temperatureresponsive valve.

Upper housing 12 has a flange 61 surrounding its lower edge and a hole62 in its upper surface. Hole 62 is aligned with hole 50 in plate 14 andprojection in lower housing 10. A pair of tubes 64 and 66 are fastenedto one side of upper housing 12.

An internally threaded cap member 68 having a hexagon head 70 and anenlarged integral washer 72 is also used in the control mechanism. Ahole '74 is formed in the wall of member 68 and an O ring seal 75 isadapted to lit the cylindrical portion of member 68.

The control mechanism is assembled in the following manner. First theflanged end 28 of valve body 26, which contains its internal components,is located in projection 20 so a hole in the bottom of projection 20communicates with the hole in jet 44. A seal 48 is positioned onshoulder and plate 14 is positioned on seal 48 with the external screwthreads 32. projecting through hole 50. Plate 14 rests on shoulder andan O ring (not shown) can be located between plate 14 and shoulder 30 ifnecessary for sealing purposes.

Upper housing 12 fits on plate 14, usually with another seal (not shown)similar to seal 48 interposed between flange 61 and plate 14. Lip 24assists in properly locating plate 1 upper housing 12, seal 48 and itscorresponding seal. Valve body 26 terminates Within chamber 18 belowhole 62.

O ring 75 is slipped onto the cylindrical portion of cap member 68 andmember 68 is inserted through hole 62 and threaded onto threads 32 untilit seats on plate 14. Hole 74 is located so it is above the top ofthreads 32 and bore 36 communicates with chamber 18 through hole 74.

Referring now to FTGURE 2, numeral 76 designates a carburetor serving inthe embodiment as the metering device, numeral 78 designates a portionof the intake manifold, and numeral 80 designates a portion of a dualdiaphragm distributor for an internal combustion engine. Carburetor 76has an induction passage 82 containing a conventional signal generatingventuri section 84 and a throttle blade 86. Below throttle blade 86,induction passage 82 communicates with passage 88 in intake manifold 78.

The main housing 90 of the dual diaphragm distributor 80 contains thedistributor advance plate 92 plus the distributor cam and otherconventional distributor components (not shown). Rotation of thedistributor cam is counterclockwise. Connected to the exterior ofhousing 90 is the vacuum advance motor housing 94. A diaphragm 96 formsan outer vacuum chamber 98 in housing 94 and a second annular shapeddiaphragm 100 forms a second chamber 102 in housing 94. An arm 104connects diaphragm 96 with the advance plate 92 in the distributor. Acompressive spring 106 bearing on diaphragm 96 is mounted in chamber 98and acts through diaphragm 96 and arm 104 to urge advance plate 92toward a counterclockwise or retarded position.

Similarly, a spring 103 mounted in chamber 102 acts on diaphragm 100 tourge diaphragm 100 in the opposite direction. Diaphragm 100 is fastenedto a position plate 110 that seats on a portion of housing 94represented by numeral 112 when spring 103 is extended to its maximumposition and seats on the portion represented by numeral 113 when avacuum in chamber 102 draws the position plate to the left. The innerportion of plate 110 is adjacent a cup-shaped stop member 114 fastenedto diaphragm 96.

Projection 29 of the control mechanism of this invention fits intointake manifold 78. A hose 116 connects a port 118 located just anteriorof throttle blade 86 with tube 64 on upper housing 12. Another hose 120connects tube 66 with chamber 98 in housing 94 and another hose 122connects tube 23 with chamber 102 of housing 94.

4 In the FIGURE 2 embodiment, tube 22 is capped or plugged by anyconventional means.

OPERATION While the engine is operating at road load or is accelerating,the vacuum signal appearing at port 118 is transmitted through hose 116,upper chamber 18, and hose 120 to chamber 98 where the signal positionsdiaphragm 96. Upper chamber 18 then is isolated from lower chamber 16,which is accomplished by selecting spring 42 so valve 40 remains seatedunder the relatively low manifold vacuum signals involved and selectingbimetal 68 so 0 ring 58 is held in contact with plate 14 at thetemperatures involved. Manifold vacuum exists in lower chamber 16 and istransmitted to chamber 102 by hose 122, but the portion 112 of housing94 prevents interference with the position of diaphragm 96 by theposition of diaphragm 100.

When the engine is idling at temperatures up to normal, the vacuum atport 118 is substantially Zero and consequently the vacuum in chamber 98also is substantially zero. Spring 106 moves diaphragm 96 to the leftuntil stop member 114 contacts plate 110. The manifold vacuum at idle isrelatively high (i.e., 15-18 inches of mercury) and a vacuum signal istransmitted through jet 44 and hole 46 into lower chamber 16. Hose 122transmits the signal to chamber 102 where it overcomes the force ofspring 108 and moves diaphragm to the left against portion 113 ofhousing 94. This permits spring 106 to move diaphragm 96 further to theleft than pictured, thereby turning plate 92 counterclockwise andretarding the ignition.

The air flow over the engine at engine idle is reduced sufficiently sothe heat transfer through the metal walls of the manifold renders thetemperature of the control mechanism representative of enginetemperature. If engine temperature rises, the temperature of bimetalstrip 60 also rises and eventually strip 60 moves cylindrical member 54upward, thereby moving 0 ring 58 out of contact with plate 14. A vacuumsignal representative of the manifold vacuum existing in chamber 16 thenis transmitted into chamber 18 and via hose to chamber 98. In chamber 98the vacuum signal draws diaphragm 96 to the right, thereby advancing theignition timing.

During decelerations, manifold vacuum rises above the values of manifoldvacuum at engine idle (e.g., 23-25 inches of mercury). The highermanifold vacuum is applied through jet 44 to valve 40 and pulls valve 40off shoulder 38. A vacuum signal then passes through bore 36 and hole 74into upper chamber 18 and via hose 120 to chamber 98. In chamber 98, thevacuum draws diaphragm 96 to the right and thereby advances the ignitiontiming.

The sizes of the orifice in jet 44, hole 46, and hole 74 can be selectedso vacuum signals less than but representative of manifold vacuum appearin lower chamber 16 and upper chamber 18. Hole 46, hole 74, valve 40 andhole 52 and valve member 54 can be selected so the vacuum signalappearing in chamber 18 during deceleration differs from the signalduring hot idling.

Usually the signal in the upper chamber is about four to five inches ofmercury when either of the pressure or temperature responsive valves areopen. Note, however, that full manifold vacuum can be supplied to upperchamber 18 during deceleration while modulated vacuum is supplied duringhot idling. A restriction can be insorted in tube 64, hose 116 or port118 to prevent the vacuum signals appearing in upper chamber 18 wheneither the pressure or temperature responsive valve is open from beingtransmitted back to induction passage 82. In a preferred arrangement,hole 46 modulates the vacuum signal in chamber 16 to control theincrease in engine idling speed when the temperature responsive valveopens, because full manifold vacuum can increase idling speed by severalhundred r.p.m.s. Tapering member 54 produces the same control with theadded feature of proportioning the speed increase to the temperature.

The dual diaphragm distributor used in the illustrated embodimentprovides extra retardation of the ignition timing at idle. Of course,the control mechanism of this invention can be used with a conventionalsingle diaphragm distributor lacking this feature. If desired, port 118can be located in the carburetor venturi 84 or the signal for port 118can be taken from a passage commuuicating with the venturi and theillustrated location just anterior of the throttle blade, withappropriate metering jets.

Since cap member 68 seats on plate 14 which in turn seats on shoulder30, member 68' combines with body 26 to form a rigid structure extendingvertically through the control mechanism so a force suflicient to pressprojection 20 into the opening in the intake manifold can be applied tothe top of member 62. This arrangement greatly simplifies assembly ofthe control mechanism into the engine. If desired, hole 50 can beenlarged so member 68 seats directly on shoulder 30. Tube 22 can be usedas a hose connection for routing manifold vacuum to other vehiclecomponents.

Thus, this invention provides a unitary control mechanism for advancingignition timing during engine deceleration and hot idling. The controlmechanism is relatively inexpensive to build and assemble into vehicles,does not interfere with ignition timing during other operating phases,and permits varying the amount of advance during deceleration from theamount of advance during hot idling.

We claim:

1. In a reciprocating internal combustion engine having a meteringdevice with an induction passa e containing a throttle blade forsupplying air to an intake manifold of said engine and having anignition distributor for distributing ignition producing energy to saidengine, a distributor control mechanism comprising:

a housing attached by heat conducting means to the intake manifold,

a partition dividing said housing into first and second chambers withthe first chamber connected to the interior of the intake manifold .andthe second chamber connected to the induction passage anterior of thethrottle blade,

passage means connecting said second chamber to an ignition timing meansfor the distributor, and

thermally responsive valve means located within said housing forconnecting said first chamber to said second chamber, said thermallyresponsive valve means connecting said first and second chambers whenengine temperature exceeds a predetermined maximum, said thermallyresponsive valve means being responsive to the temperature of the intakemanifold.

2. The engine of claim 1 in which the thermally responsive valve meansis located in the partition and comprising ressure responsive valvemeans located within said housing for connecting said second chamber tothe intake manifold interior, said pressure responsive valve meansmaking such connection when manifold vacuum exceeds a predeterminedmaximum.

3. The engine of claim 2 in which the control mechanism comprises acylindrical member having an axial passage therein, said cylindricalmember being positioned in said housing and extending through saidpartition with the bottom of said passage communicating with the intakemanifold and the top communicating with the second chamber, saidcylindrical member having an opening in its wall to connect the firstchamber to the intake manifold via the lower part of said axial passage,said pressure responsive valve means being located in said passage abovesaid opening.

4. The engine of claim 3 in which the housing of said control mechanismis pressed into a hole in the engine intake manifold.

5. The engine of claim 4 in which the control mechanism comprises a capmember threadably engaging said cylindrical member, said cap member andsaid cylindrical member having sufiicient structural rigidity totransmit a force capable of pressing the housing of the controlmechanism into the engine intake manifold.

6. The engine of claim 5 in which the ignition distributor is a dualdiaphragm distributor, the second chamber of the control mechanism isconnected to the chamber in the distributor positioning the advancediaphragm, and the first chamber is connected to the chamber in thedistributor positioning the retard diaphragm.

7. The engine of claim 2 in which the control mechanism comprises acylindrical member having an axial passage therein, said cylindricalmember being positioned in said housing and extending through saidpartition with the bottom of said passage communicating with the intakemanifold and the top communicating with the second chamber, saidcylindrical member having an opening in its wall to connect the firstchamber to the intake manifold via the lower part of said axial passage,said pressure responsive valve means being located in said passage abovesaid opening.

8. The engine of claim 7 in which the control mechanism comprises a capmember threadably engaging said cylindrical member, said cap member andsaid cylindrical member having sufiicient structural rigidity totransmit a force capable of pressing the housing of the controlmechanism into the engine intake manifold.

9. The engine of claim 1 in which the housing of said control mechanismis pressed into a hole in the engine intake manifold.

10. The engine of claim 1 in which the ignition distributor is a dualdiaphragm distributor, the second chamber of the control mechanism isconnected to the chamber in the distributor positioning the advancediaphragm, and the first chamber is connected to the chamber in thedistributor positioning the retard diaphragm.

References Cited UNITED STATES PATENTS 2,702,028 2/1955 Gintling 123-1172,809,619 10/1957 Norris 123-117 2,809,620 10/1957 Boylan 123-1172,876,754 3/1959 Obermaier 123-117 3,057,938 10/1962 Perry 123-117 X3,252,451 5/1966 Sarto 123-117 3,301,242 1/ 1967 Candelise 123-1173,081,793 3/1963 Flatt 123-117 3,162,184 12/1964 Walker 123-117 RALPH D.BLAKESLEE, Primary Examiner.

